The basic polymeric mordants useful to mordant a dye in a hydrophilic colloidal layer between a base and a photographic emulsion layer disclosed in U.S. Pat. No. 4,695,531 comprise repeating units of formula: ##STR1## wherein: R.sub.1 is hydrogen or a methyl group; A is a --COO--or a --COO--alkylene group, e.g., --COOCH.sub.2 --, --COOCH.sub.2 CH.sub.2 --, --COOCHOHCH.sub.2 --; R.sub.2 is a hydrogen or a lower alkyl group having from 1-4 carbon atoms; and X is an anion, e.g., acetate, oxalate, sulfate, chloride, or bromide. Mordant I can comprise units derived from vinylic monomers, for example, acrylates, acrylamides, vinylacetates, styrenes, vinyl ethers, vinyl ketones, vinyl alcohols, unsaturated chlorides, and nitriles with the proviso that such copolymerizable units be in a quantity of 10-20% by weight. Similar mordants with the exclusion of A in I are also disclosed in GB Patent No. 850,281.
Polymeric mordants with N-heteroarocyclic vinyl aromatic, e.g., methylvinylpyridine (picoline) are also known in the art (see, for example, Italian Patent No. 931,270).
Polyvinylpyridine-based mordant, e.g., II ##STR2## is also known in the art (see U.S. Pat. No. 4,695,531).
Non-diffusive mordants based on poly(N-vinylimidazolc) of the type IIl are known in the art (see U.S. Pat. No. 4,500,631) and have been used in certain radiographic image-forming processes wherein the mordants were coupled with water-soluble dyes. ##STR3## Polymeric mordants of the type III as well IV are also disclosed in Japanese PubIn. No. 63-307979.